Local and global magnetic properties of Zn1-xCoxO and Mn-doped GaAs thin films
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Urbano, R. R.
Pagliuso, P. G.
Katiyar, R. S.
Silva, José Humberto Dias da [UNESP]
Azevedo, G. de M.
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Institute of Electrical and Electronics Engineers (IEEE)
Amorphous and crystalline thin films of Mn-doped(0.5%-10%) GaAs and crystalline thin films of Zn1-xCoxO(x = 3%-20%) were investigated by means of magnetic susceptibility and electron spin resonance (ESR). For the Mn-doped GaAs samples, our results show the absence of ferromagnetic ordering for the amorphous films in the 300 > T > 2 K temperature range, in contrast to the ferromagnetism found in crystalline films for T-C < 110 K. A single ESR line with a temperature independent g-value (g similar to 2) is observed for the amorphous films, and the behavior of this ESR linewidth depends on the level of crystallinity of the film. For the Mn-doped GaAs crystalline films, only a ferromagnetic mode is observed for T < TC when the film is ferromagnetic. Turning now the Zn1-xCoxO films, ferromagnetic loops were observed at room temperature for these films. The magnetization data show an increasing of the saturation magnetization M. as a function of x reaching a maximum value for x approximate to 10%. ESR experiments at T = 300 K in the same films show a strong anisotropic ferromagnetic mode (FMR) for x = 0.10.
dilute ferromagnetic semiconductors, electron spin resonance, magnetization curves
IEEE Transactions on Magnetics. Piscataway: IEEE-Inst Electrical Electronics Engineers Inc., v. 42, n. 10, p. 2700-2702, 2006.